Many known cooling systems for marine engines utilize glycol for cooling. These systems are often referred to as “closed” cooling systems because cooling fluid is continuously circulated though the system in a closed loop. Closed cooling systems are relatively expensive and complicated, requiring at least two pumps and a heat exchanger to transfer heat to sea water.
Other cooling systems for marine engines utilize sea water for cooling. These systems are often referred to as “open” systems. Sea water is pumped from an inlet port to the power head of the engine and then to an outlet port for discharge from the engine. The water typically is not recirculated through the engine. In some open cooling systems, an exhaust conduit associated with the engine is also cooled with the water after it has already cooled the power head of the engine. In these examples, the water typically exits the power head at thermostat temperature and then cools the exhaust conduit before exiting via an outlet port.